Organosilicon nitriles



United States Patent 2,906,767 ORGANOSILICON NITRILES 7 Claims. (Cl. 260-4483) The present invention relates to certain organosilicon nitriles in monomeric, polymeric, or copolymeric form and which are characterized by the structure v z HF QrJ K HDQSE as explained in detail below. a

The preparation of organosilicon nitriles characterized by a structure such as NEG (CH %iR has been shown in my copending application No. 522,827 filed July 18, 1955. These can be prepared, for example, by reacting RHSiCl with in the presence of a catalyst consisting of platinum deposited on charcoal. The dichlorosilane adductis then hydrolyzedto prepare the corresponding siloxane. It will be noted that in such compounds the cyanide radical is in a terminal position with respect to the silicon atom.

I have now found that organosiloxanes having improved properties, particularly in regard to the strength and/or stiffness of rubbers or resins prepared therefrom, can be obtained when the cyanide radical is in a non-terminal position according to that illustrated above. Thus this invention relates to (1) monomericsilanes having the formula 2=C C z)2 2)zSlR=Ya=]a EN where R is a monovalent hydrocarbon radical free of aliphatic unsaturation, Y is of the group Cl, Br, and

alkoxy, Z is of the group H and COOR' where R.

is an alkyl radical of from 1 to 8 inclusive carbon atoms, a is an integer of from 1 to 2 inclusive, and x is an integer of from 0 to 2 inclusive, and (2) siloxanes containing polymeric units of the formula EN 4 T where R, Z, a, and x are as above defined.

The monomers where Z is the radical COOR' can be prepared by reacting R HSiY with the appropriate alkyl diallylcyanoacetate, R and x being as above defined, in the presence of platinum deposited on charcoal or chloroplatinic acid as a catalyst. The silane can add to one allyl group to form those compounds where a is 1 or to both groups to form those compounds wherein a is 2. Both products are formed to some extent regardless of reaction conditions, but the relative amounts of either can of course be greatly influenced by main- Patented Sept. 29, 1959 ICC taining one or the other of the reactants in excess. The reaction can be represented. as follows:

In the silane reactant, R can be any monovalent hy-.

drocarbon radical free of aliphatic unsaturation, e.g. alkyl such as methyl, ethyl, propyl, and octadecyl; aryl such as phenyl and xenyl; cycloaliphatic such as cyclo hexyl, alkaryl such as tolyl, and aralkyl such as benzyl. Where more than one R radical is present on a particular silicon atom it can represent the same or different radicals. Y can be Cl, Br, or an alkoxy radical, and of the latter a radical of from 1 to 8 inclusive carbon atoms is preferred. The Y radicals can also be the same or different radicals. Examples of preferred silane reactants include HSiCl Mel-lSiCl M eHSi(OEt)Cl, MePhHSi(OEt), Ph HSi(OMe), HSiBr and The symbols Me, Et, Bu, and Ph are used above an throughout this specification to represent methyl, ethyl, butyl, and phenyl radicals respectively.

In the cyanoacetate reactant, R is an alkyl radical of from 1 to 8 inclusive carbon atoms, e.g., methyl, ethyl, and octyl. l

The monomers where Z is a hydrogen atom are prepared in the same manner; except that diallylacetonitrile [i.e. (CH =CHCH CHCN] is the'reactant in place of the alkyl diallylcyanoacetate. Here again the silane can add to either one or both of the allyl radicals to form the corresponding monomeric adducts.

In the reactions by which all of the above monomers are prepared, the optimum reaction temperature varies over a Wide range, depending not only upon the particular reactants present but also upon the type and amount of catalyst employed. Ordinarily a reaction temperature in the region of to C. is preferred. Atmospheric, or subor superatmospheric pressures can be employed as desired.

The chloroplatinic acid catalyst is preferably employed in the form of the hexahydrate, l-l Ptcl -ol-l o. Since only minute amounts are needed (in the region :of 1 l0- to 1 10--' mole per mole of the silane), handling is facilitatedby the use of a solution of the acid in an appropriate solvent, e.g. in an alcohol such as ism propanol or a glycol ether such as the dimethylether of diethylene glycol. In general this catalyst permits the use of less platinum, lower reaction temperatures, and a shorter reaction time than when platinum deposited on charcoal (hereafter designated Pt/C) is the catalyst.

The Pt/C catalysts are available commercially,'or they can be prepared by dissolving H PtCl -til-lgO in Water, neutralizing to a pH of about 10 with KOH, suspending charcoal in the solution, bubbling hydrogen through the slurry to precipitate the platinum, and then washing and drying the finely divided solids. It is preferable that the final catalyst contain from about 1 to 5 percent Pt by weight, and the catalyst mass itselfis generally employed in an amount of about 0.5 to 2 percent by weight based on the weight of thesilane. Large uct is a copolymer. In either case the siloxane consists essentially of units of the formula GEN T as defined above. Such polymers tend to be resinous when x has an average value of from up to about 0.9, then of a rubbery or viscous fluid nature up to an average value of about 1.1, then of a decreasingly viscous fluid nature as the value rises to 2.

A second type of copolymer within the scope of this invention is that which contains both polymeric units of the above type and units of the formula R bSiO preferably there being at least 0.1 molar percent of the former units present. In the latter units, R" represents monovalent hydrocarbon radicals or halogenated monovalent hydrocarbon radicals and b is an integer of from 0 to 3 inclusive. Although b can be 0 in some of the individual units, its average value when considering all of such units present in the copolymer should be from 0.8 to 3 inclusive. Thus the latter units will be of the type R"SiO R" SiO, and R" SiO along with SiO units to the extent that the average number of R radicals is maintained up to at least 0.8 per Si atom in the polymeric units in question. The R" radicals can be the same or different radicals within any particular unit or within the whole couolymeric radical.

Examples of suitable R" radicals include any of the R radicals illustrated above, as well as alkenyl radicals such as vinyl, allyl, hexenyl and cyclohexenyl; and halogenated monovalent hydrocarbon'radicals such as chlorophenyl, dichlorophenyl, bromophenyl, tetrabromoxenyl, tetrafluoroeth l, u,a,a-trifluorotolyl, chlorovinyl, and 1,1,1-trifluoropropyl radicals. 'As is usual with organosilicon compounds, those polymers and copolymers in which R and R" are methyl and/or phenyl radicals are preferred for their thermal stability. Thus when any R" substituted polymeric units are present it is preferred that they be of the formula where b is O to 3 inclusive, 6 is 0 to 2 inclusive, the sum of b+c is not greater than 3, and the average value of the sum of b+c is from 0.8 to 3 inclusive.

Copolymers of the type discussed above can be prepared by the cohydrolysis of any one or more of the monomers of this invention as mixed with one or more monomers of the formula R" SiY where R", Y, and b are as defined above. The latter are well-known materials, many of which are commercially available. The usual and well-known techniques of organosilicon hydrolysis are applicable.

Similar copolymers can be prepared by the catalytic copolymerization of the corresponding siloxanes, providing all such siloxanes are in a fluid state or solvent soluble state prior to the copolymerization thereof. The well-known acid or alkaline siloxane rearrangement catalysts can be employed in the latter method, provided that conditions are such that the nitrile or -COOR' groups are not hydrolyzed. In general it is preferable to carry out the copolymerization under anhydrous conditions .and at temperatures below 100 C. Polar solvents such as acetonitrile can be used to facilitate the interaction and copolymerization if desired. It is to be understood that the defined siloxane polymers and copolymers of this invention can contain small amounts of unhydrolyzed Y radicals or uncondensed OH radicals attached to some of the silicon atoms therein, as is conventional with the vast majority of organosiloxane polymers.

The resinous, rubbery, or fluid nature of the polymers 4 and copolymers herein will depend largely upon the average degree of substitution (i.e., the ratio of total organic groups to total silicon atoms), following much the usual pattern of organosiloxane polymers. The products are useful in the same applications as the well-known silicone fluids, resins, and rubbers, e.g. as potting and sealing compounds, electrical insulation, gasketing, impregnating varnishes, and the like; and if desired can be used in conjunction with the conventional fillers such as silica aerogel, fume silica, titania, crushed quartz, ferric oxide, zinc oxide, and asbestos or glass fibers. Rubbers can be prepared from the polymers and copolymers having an average degree of substitution of about 2.0 by the usual organosiloxane rubber compounding techniques, and they are characterized by an improved resistance to swelling in hydrocarbon solvents.

The following examples are illustrative only.

Example 1 A slight theoretical excess of Me HSiCI was added to i removed therefrom by flash distillation, a fluid polymer is obtained of the formula Me [(CH1=CHCH C (CN) (CO OEt) (CHzCHICHfi P'HZQ Hydrolysis of the B product in the same fashion provides a very viscous fluid containing polymeric units of the formula Me Me [O.$S (OH2);]C(CN)(COOEt)[(CH2)3 iOJ] it. Me

Example 2 By the method of Example 1, 1.1 moles Me HSiCl was reacted with 0.5 mole diallylacetonitrile in the presence of 1 g. of 2 percent Pt/C catalyst. Again distillation of the reaction mass yielded two product fractions:

(A) [C1Me Si(CH ]CH(CH CH=CH (CN) boiling at 93 C./3 mm. Hg, and (B) boiling at 142 C./3 mm. Hg. Hydrolysis of these two fractions as in Example 1 produces the corresponding disiloxane fluid and a very viscous fluid containing polymeric units of the formula Example 3 When 1.1 moles PhI-ISiBr is reacted with 0.5 mole diallylacetonitrile by the method of Example 1, there are obtained the two products: (A)

and} (-B)' nr rhsitcn n cincm. whea the A product is hydrolyzed according to Example 1, a viscous polymer of the type x (CH:=CHCH:) H(01 I) (omomcrnsto) is obtained.- Hydrolysis of the B product gives a polysiloxane containing units of the formula.

If: 1 h

I K MI U N?[( m Example 4 To 0.2 mole diallylacetonitrile containing 0.25 g. of percent Pt/C there was added 0.4 mole Me HSi(OEt). The mixture was heated overnight at 100-140 C., and upon filtration and distillation there were obtained two product fractions: (A)

'[(Et0) Me Si(CH ]CH(CN) (CH,CH=CH,) boiling at 135 C./13 mm. Hg, n 1.4410, a, 0.8847; and (B) [(EtO)Me Si(CH CH(CN) boiling at 150 C./ 3 mm. Hg, n 1.4406, (1 0.9020.

Example 5 The reaction of HSiCl and diallylacetonitrile in the manner of Example 1 produces the compounds The reaction of MeHSiCl and ethyl diallylcyanoacetate in the manner of Example 1 produces the compounds (A) [Cl MeSi(CH C(CH C H=CH (CN) (COOEt) and (B) [Cl MeSi(CH C(CN)(COOEt). When a mixture of 0.8 mole of (A), 2 moles MeSiCl 1 mole PhSiCl and 0.2 mole Ph SiCl is dissolved in toluene and cohydrolyzed by adding it to an excess of water,

the washed cohydrolyzate is a toluene solution of a resinous copolymer containing molar percent (CH =CHCH )C(CN) (COOEt) [CH CH CH Si(Me)O] units, 50 molar percent MeSiO units, molar percent PhSiO units, and 5 molar percent Ph SiO units. When an equimolar mixture of (B) and CH =CHSiCl is cohydrolyzed in the same manner, a resinous copolymer is obtained which contains 50 molar percent of units of the formula [OSi(Me) (CH ]C(CN) (COOt) [(CH (Me)SiO] and 50 molar percent of units of the formula CH =CHSiO Example 7 The reaction of MeHSiCl and diallylacetonitrile in the manner of Example 1 produces the compounds (A) [Cl MeSi(CH (CHCH CH=CH (CN) and (B) Hydrolysis ofithe B product gives a viscous stickypolysiloxane containing units of the formula [OSi(Me) (CH ]CH( CN[(CH) (Me)SiO] The latter can be mixed with an equimolar amount of (Me SiO) and 1 percent by weight of sulfuric acid, and

upon standing at room temperature a rubbery copolymer is obtained containing the above units and Me SiO units.

That which is claimed is: t 1. An organosilicon nitrile having the formula Z FCHCHI)l-l+[( 2)3 lRI l ]l GEN where R is a monovalent hydrocarbon radical free of aliphatic unsaturation, Y is of the group consisting of Cl, Br, and alkoxy, Z is of the group consisting of H and -COOR' where R is an alkyl radical of from 1 to 8 inclusive carbon atoms, a is an integer of from 1 to 2 inclusive, and x is an integer of from 0 to 2 inclusive.

2. An organosilicon nitrile having the formula (cH,=oHcHl)= .OH[(0H= ,si(clmcmnon.

where a is an integer of from 1 to 2 inclusive.

3. An organosilicon nitrile having the formula F OHQHC(COOO:Hs)l( s)i 1].

where a is an integer of from 1 to 2 inclusive.

4. An organosilicon nitrile having the formula 2=CHCHg)2n 2)3 I)2( l 6)]l where a is an integer of from 1 to 2 inclusive.

5. An organosiloxane in which at least 0.1 molar percent of the polymeric units are of the formula i FCHCH2)2e 2)3S1R=o o N T where R is a monovalent hydrocarbon radical free of aliphatic unsaturation, Z is selected from the group consisting of H and COOR' where R is an alkyl radical of from 1 to 8 inclusive carbon atoms, a is an integer of from 1 to 2 inclusive, and x is an integer of from 0 to 2 inclusive, the remaining polymeric units being of the formula where b is an integer of from 0 to 3 inclusive and has an average value of from 0.8 to 3 inclusive, and R is selected from the group consisting of monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals.

6. An organosiloxane in which at least 0.1 molar percent of the polymeric units are of the formula GEN I 2 z).

where a is an integer of from 1 to 2 inclusive and x is an integer of from 0 to 2 inclusive the remaining polymeric units being of the formula where b is an integer of from 0 to 3 inclusive, 0 is an integer of from 0 to 2 inclusive, and the sum of b+c is not greater than 3, the average value of the sum of b+c in said remaining polymeric units being from 0.8 to 3 inclusive.

s 7, A nrganosiloxane in which at least 0.1 molar perwhere b is an integer of from 0 to 3 inclusive, 0 is an cent of the polymeric units are of the formula integer qf from 0 to 2 inclusive, and the sum of b+c u l is not greater than 3, the average value of the sum of (GHWGHCH), zi f igi b+c in said remaining polymeric units being from 0.8 to

5 3 inclusive.

Ha): where a is an integer of from 1 to 2 inclusive and x is Rderences Cited in the file of this Patent an integer of from 0 to 2 inclusive, the remaining poly- FOREIGN PATENTS meric unit? being Ofthe fmmula 1,116,725 France Feb. 6, 1956 cnmo nmsio 1,116,726 France Feb. 6, 1956 UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,906,767 September 29, 1959 Leo H. Sommer It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 66, the formula should read as shown below instead of as in the patent:

[OSi(Me)(0112):]0(ON)(CO0Et)[(CHz):(Me)SiO} column 6, line 22, the formula should read as shown below instead of as in the patent: (CHFCHCHDa-ICHKCHMSK011:):01].

EN line 60, the formula should read as shown below instead of as in the patent:

(CHFCHCHmqCHI:(CHa)|8i0 GEN (C31), column 7, line 10, the formula. should read as shown below instead of as in the patent:

( I)a(C H;)SiO I 3 Signed and sealed this 3rd day of May 1960.

Attest: KARL H. AXLINE,

Attestz'ng Officer.

ROBERT C. WATSON, Gamm'ssz'oner of Patents. 

1. AN ORGANOSILICON NITRILE HAVING THE FORMULA
 5. AN ORGANOSILOXANE IN WHICH AT LEAST 0.1 MOLAR PERCENT OF THE POLYMERIC UNITS ARE OF THE FORMULA 